1. Technical Field
The present invention relates to a transmissive display device that allows a user to visually recognize contents as virtual images and a method of controlling the transmissive display device.
2. Related Art
In related art, as a kind of transmissive display device, a head mounted display device (head mounted display: HMD) using a transmissive display having a spectacle shape worn on a head has been known. For example, in a head mounted display of Non-Patent Document 1 (See-Through Mobile Viewer MOVERIO BT-100 User's Guide, Epson Sales Japan Corporation, Seiko Epson Corporation, page 12 (http://dl.epson.jp/support/manual/data/moverio/bt100/U_GUIDE_BT100.PDF)), screen brightness is manually adjustable according to contents to be viewed and use environment brightness. When reading an electronic book with a darker background color, a user is harder to see character information because the user can see an external world well through a virtual display area in which a virtual image is displayed, and adjusts the screen brightness to be higher. To the contrary, when reading an electronic book with a lighter background color, the user can clearly see character information because the user cannot see the external world well through the virtual display area, and adjusts the screen brightness to be lower.
However, in the head mounted display of related art, manual adjustment of the screen brightness is required for the user and the operation is troublesome. Further, recently, industrial application of display of manuals, operating instruction information, etc. on the head mounted display device has attracted attention. The brightness adjustment during operation is not only troublesome but also causes operation errors, and improvements are desired.